This section is intended to introduce the reader to various aspects of art, which may be associated with embodiments of the present invention. This discussion is believed to be helpful in providing the reader with information to facilitate a better understanding of particular techniques of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not necessarily as admissions of prior art.
Producing oil and gas from subterranean formations has become increasingly challenging over the years, requiring continuing innovation in nearly every aspect of oil and gas operations. The continuing innovation enables current and future wells to reach reserves in reservoirs that were previously uneconomical. For example, multi-zone wells increase the efficiency of a single well, ultra-deep water wells access previously unreachable reservoirs, wells of greater depth and/or of extended reach wells may enable access to new and/or different reserves from new and/or existing wells, drilling and completion advances allows production from high pressure/temperature reservoirs, reservoirs having long intervals, reservoirs having high production rates, and reservoirs in remote locations. However, the technologies utilized to overcome the challenges increase the individual well cost dramatically and demands fewer wells for an economical field development. Consequently, the well productivity, reliability, and longevity become vital to avoid undesired production loss and expensive intervention or workovers.
As described above, many wells include multiple zones in one more intervals that may be of extended lengths. During operation of wells having multiple zones, it is important to control and manage fluids flowing to and from different zones. For example, in production operations, proper control of the fluid production rates in various zones can result in delaying water/gas coning and in maximizing reserve recovery. Various techniques are known to determine whether zonal isolation will be effective or desirable and where in a well to position the zonal isolation. Exemplary implementations of zonal isolations and inflow control devices installed in wells have been documented in various publications, including M. W. HELMY et al., “Application of New Technology in the Completion of ERD Wells, Sakhalin-1 Development,” SPE 103587, October 2006; and David C. HAEBERLE et al., “Application of Flow-Control Devices for Water Injection in the Erha Field”, SPE 112726, March 2008.
Exemplary operating conditions known to benefit from the use of zonal isolation technologies include the untimely production of water, gas, or other undesirable formation fluids. Water can be produced together with hydrocarbonds during well production for a number of reasons, including the presence of native water zones, coning (rise of near-well hydrocarbon-water contact), high permeability streaks, natural fractures, and fingering from injection wells. Depending on the mechanism or cause of the water production, the water may be produced at different locations and times during a well's lifetime. Careful installation of zonal isolation in the initial completion allows an operator to shut-off the production from one or more zones during the well lifetime to limit the production of water or other desirable fluids.
Zonal isolation in open-hole completions is becoming increasingly more important for establishing and maintaining optimized long-term performance of both injection and production wells. In cases where gravel pack is needed for sand (particle) control, multi-zone gravel packing with zonal isolation in openhole completions had been challenging until the internal shunt alternate path technology was introduced. The internal shunt alternate path technology is described at least in U.S. Publication No. 2008/0142227, which is incorporated herein by reference in its entirety for all purposes, and M. D. BARRY et al., “Openhole Gravel Packing with Zonal Isolation,” SPE 110460, November 2007. Zonal isolation in a open-hole, gravel-packed completion could be provided by a conventional packer element and secondary flow paths to enable both zonal isolation and alternate path gravel packing, such as described in U.S. Publication Nos. 2009/0294128 and 2010/0032158, which are each incorporated herein by reference in their entirety for all purposes. For example, enlarged and/or irregular boreholes, high pressure differentials, increasing number of zones per well, high temperatures, and temperature fluctuations each can challenge, and sometimes compromise, the effectiveness of the alternate path systems. In addition to these challenging environmental conditions, the operating conditions further complicate the efforts to provide a reliable, robust solution. For example, the longevity of the zonal isolation equipment is increasingly important as wells are required to produce for longer periods of time between workovers and treatment operations. Moreover, the risk or likelihood of water and/or gas production increases over the life of the well (due to increasing drawdown and depletion) requiring zonal isolation equipment that can endure the conditions of the well for extended periods.
For one or more of these reasons, there is a continuing need for improved zonal isolation technologies. Improved zonal isolation technologies would preferably provide one or more improvement such as being less sensitive to downhole conditions, being more forgiving of operational variables, being more flexible in its use and capabilities, being operationally easy to run into the well, position, and set, and/or being mechanically simple to improve tolerance to well conditions over time.
Prior efforts to improve upon mechanical packers for zonal isolation have provided improvements such as swellable packers. Still additional developments include the use of an annular gravel pack between a blank basepipe segment and a wellbore wall having very low permeability, such as a shale section of the well. The annular gravel pack forms an axial zonal isolation and provides substantial flow resistance. However, it is not possible for such gravel pack barrier to form without introducing a proper fluid leakoff path to dehydrate the gravel slurry. Due to the low permeability of the formation, the fluid leak-off in such implementations is through the basepipe to return to surface. One example of such a system is seen in U.S. Pat. No. 6,520,254 to Hurst et al. However, if any leak-off path exists, water or gas production will follow the same path and render the isolation functionality of the gravel pack ineffective. Accordingly, there is a continuing need for zonal isolation systems and methods.
Other related material may be found in at least U.S. Pat. Nos. 7,527,095; 6,318,465; 6,619,397; and 7,108,060.